The present invention relates to an alignment apparatus which is interposed between a machine main body such as a robot and a terminal body such as a finger device, a hand device, or the like, and performs alignment therebetween to have a predetermined compliance.
As a conventional alignment apparatus used in an assembly robot as an automatic assembly apparatus, Japanese Patent Publication No. 61-34932 discloses an apparatus which couples a robot main body and a finger device using a plurality of leaf springs, and utilizes elasticity of these leaf springs. Japanese Patent Laid-Open (Kokai) Nos. 57-168840 and 62-103990, and U.S. Pat. No. 3,824,674 disclose arrangements wherein a robot main body and a finger device are coupled using coil springs in place of the leaf springs.
The alignment apparatus is required to have an arrangement of allowing deviations of the robot and the finger device and of recovering the deviations. U.S. Pat. Nos. 4,609,325, 4,179,783 and 4,098,001 disclose arrangements in which deviations of the robot and the finger device are allowed and recovered using a bearing means and an elastic member.
Such conventional alignment apparatuses employ springs having directivity of deviation. For this reason, the deviating direction of the finger device is limited. In the conventional alignment apparatus, in order to carry out a precise alignment operation, the arrangement becomes complicated.
An assembly operation of articles by a robot has merit since it can be performed at high speed and high precision within a unit time. When such a high-speed operation is carried out, assembly positions of an article gripped by the finger device and a corresponding member are shifted from each other. For this reason, the finger device is deviated relative to a robot arm to execute the assembly operation. Upon completion of the assembly operation, the finger device is recovered to an original position. The time required for the recovery operation of the finger device and the time required for completely stopping the finger device are preferably short. In particular, if the stopping time is long, the next operation of the robot becomes unstable.